The possibility of a malignant haematological disorder should be kept in mind when the patient’s symptoms or signs include e.g. fever of unknown origin, increased susceptibility to infection, lymphadenopathy, hepatosplenomegaly, cytopenia of several cell lines, significant cytosis, or bleeding or thrombotic tendency.Conditions requiring urgent or emergency treatment in hospital, such as aggressive lymphomas, acute leukaemias, complicated myeloma and myeloproliferative diseases should be recognized.